The embodiment described herein relate to a method for manufacturing a semiconductor device, and more specifically, to a method for forming a contact hole of a semiconductor device.
High storage density, rapid operation rates, non-volatility, low production cost, and low power consumption, all of which are important development factors of semiconductor memory devices. In order to satisfy these conditions, the size of the semiconductor memory device is increasingly reduced, and thus it is important to form highly resolved contact holes with uniform diameter throughout the length of the holes.
In particular, manufacturing a phase-change random access memory (PRAM) device involves processes for forming highly resolved contact holes in a high density configuration. However, problems occur using conventional methods of forming contact holes in a high density configuration because the holes are not fully opened. For example, a bridge may occur.
The formation of contact holes with an increased depth using conventional methods also results in a difference between the upper and lower diameter of each hole, thus reducing the performance of the device.
Further, another problem with the conventional methods of creating a high density configuration of contact holes arises when the intervals between the contact holes are reduced. The desired number of contact holes cannot be formed in a single process. Accordingly, the process for forming the contact holes must be repeated several times, thus increasing the number of steps of the process.